FORMATION AND ELIMINATION OF SYNAPSES

我研究的长期目标是研究心绞痛的基本机制 突触的形成、消除和可塑性。其中最 突触的重要结构是递质释放的位置： 活动区。根据这项提议，青蛙的神经肌肉连接将是 在不同情况下使用细胞内记录和 冷冻断口电子显微镜。主要目标是研究： (I)活性区膜的细胞化学和分化。 Filipin已被用作膜胆固醇的细胞化学探针。 在大多数区域都可以看到独特的纤毛脂-甾醇复合体。 冰冻断裂的突触前膜，但没有活动区。 这种膜异质性的分化，尤其是与 活动区粒子和结合部褶皱，将通过处理 退变、再生和修复过程中神经肌与菲立普林的连接 发展。多神经支配时细胞膜异质性的变化 还将检查端板，特别是在消除 幼蛙体内的突触。胆固醇对递质释放和代谢的影响 活跃区细胞化学将通过应用富含胆固醇的 脂质体到正常的连接处。 (Ii)交错后褶皱对活动带形成的影响(1) 通过移除原始终板将重新诱导异位连接 并将原始神经植入无印记区域。形成 之前没有交界褶皱的异位地点的活动区将是 与原活动区再生的考察和比较 具持久接合折叠的端板。(2)迷走神经-肌肉连接 将迷走神经植入失神经骨骼肌而形成。 在这些交界处，将检查活动区域是否重新生成 它们的原始结构发现于正常的迷走神经终末或分化 在运动神经末梢中可以看到两个双排颗粒。 拟议的研究将阐明独特的组织和 活动区的细胞化学被诱导、分化和维持。 它还将使我们更好地理解 神经递质释放。这些基础知识将产生很大的影响 了解学习、智力发展的机制，以及 某些发育性神经障碍。

The long term goals of my research are to study the basic mechanisms of formation, elimination and plasticity of synapses. One of the most important structures at the synapses is the site of transmitter release: the active zone. Under this proposal frog neuromuscular junctions will be studied in various situations using intracellular recording and freeze-fracture electron microscopy. The major objectives are to study: (I) Cytochemistry and differentiation of the active zone membranes. Filipin has been used as a cytochemical probe for membrane cholesterol. Distinctive filipin-sterol complexes are seen in most areas of freeze-fractured presynaptic membranes but are absent from active zones. Differentiation of this membrane heterogeneity, especially in relation to active zone particles and junctional folds, will be studied by treating neuroomuscular junctions with filipin during degeneration, regeneration and development. Changes in membrane heterogeneity at multiply-innervated endplates will also be examined, particularly during elimination of synapses in young frogs. Effects of cholesterol on transmitter release and active zone cytochemistry will be studied by applying cholesterol-rich liposomes to normal junctions. (II) Influence of postjunctional folds on the formation of active zones (1) Ectopic junctions will be induced de novo by removing the original endplate zone and implanting original nerves to enplate-free areas. Formation of active zones at ectopic sites with no previous junctional folds will be examined and compared with regeneration of active zones at original endplates with persisting junctional folds. (2) Vagus-Muscle junctions will be formed by implanting vagus nerves to denervated skeletal muscles. At these junctions it will be examined whether active zones regenerate to their original structures found at normal vagal terminals or differentiate into two double rows of particles as seen in motor nerve terminals. The proposed research will elucidate how the unique organization and cytochemistry of active zones is induced, differentiated and maintained. It will also provide a better understanding of the fundamental process of neurotransmitter release. This basic knowledge will have a strong impact on understanding the mechanisms of learning, intelligence development, and certain developmental neurological disorders.